Understanding thio-effects in simple phosphoryl systems : role of solvent effects and nucleophile charge.

Recent experimental work (J. Org. Chem., 2012, 77, 5829) demonstrated pronounced differences in measured thio-effects for the hydrolysis of (thio)phosphodichloridates by water and hydroxide nucleophiles. In the present work, we have performed detailed quantum chemical calculations of these reactions, with the aim of rationalizing the molecular bases for this discrimination. The calculations highlight the interplay between nucleophile charge and transition state solvation in SN2(P) mechanisms as the basis of these differences, rather than a change in mechanism

Pleural mesothelioma and lung cancer risks in relation to occupational history and asbestos lung burden.

BACKGROUND: We have conducted a population-based study of pleural mesothelioma patients with occupational histories and measured asbestos lung burdens in occupationally exposed workers and in the general population. The relationship between lung burden and risk, particularly at environmental exposure levels, will enable future mesothelioma rates in people born after 1965 who never installed asbestos to be predicted from their asbestos lung burdens. METHODS: Following personal interview asbestos fibres longer than 5 µm were counted by transmission electron microscopy in lung samples obtained from 133 patients with mesothelioma and 262 patients with lung cancer. ORs for mesothelioma were converted to lifetime risks. RESULTS: Lifetime mesothelioma risk is approximately 0.02% per 1000 amphibole fibres per gram of dry lung tissue over a more than 100-fold range, from 1 to 4 in the most heavily exposed building workers to less than 1 in 500 in most of the population. The asbestos fibres counted were amosite (75%), crocidolite (18%), other amphiboles (5%) and chrysotile (2%). CONCLUSIONS: The approximate linearity of the dose-response together with lung burden measurements in younger people will provide reasonably reliable predictions of future mesothelioma rates in those born since 1965 whose risks cannot yet be seen in national rates. Burdens in those born more recently will indicate the continuing occupational and environmental hazards under current asbestos control regulations. Our results confirm the major contribution of amosite to UK mesothelioma incidence and the substantial contribution of non-occupational exposure, particularly in women

The role of the dominant versus the non-dominant hemisphere: an fMRI study of Aphasia recovery following stroke

Background: Speech production is one of the most frequently affected cognitive functions following stroke; however, the neural mechanisms underlying the recovery of speech function are still incompletely understood. Aims: The current study aims to address the differential contributions of the dominant and non-dominant hemispheres in recovery from aphasia following stroke by comparing data from four stroke patients and 12 control participants to assess the patterns of activation during speech production tasks during functional magnetic resonance imaging (fMRI) scanning. Methods & Procedures: Four chronic stroke patients (three left-hemisphere lesion and one right-hemisphere lesion) diagnosed with Broca’s aphasia at the acute phase, but now recovered to near normal speech ability, were tested on speech production tasks (phonemic fluency, categorical fluency and picture naming) whilst undergoing fMRI. These patients were compared with 12 healthy controls undergoing the same procedure. Outcomes & Results: Individual subject analysis showed activation peaks in perilesional areas in three out of four patients. This included one patient with right-hemisphere lesion, who also showed predominant perilesional activation. Group analysis of control participants showed predominately left-hemisphere activation, but not exclusively so. Laterality indexes were calculated and showed predominant left-hemisphere lateralisation in the control group (LI = 0.4). Three out of the four patients showed speech lateralised to the same hemisphere as their lesion and the fourth patient showed speech lateralised to the opposite hemisphere to their lesion. Different speech production tasks resulted in varying lateralisation indices (LIs) within participants. Conclusions: The data suggest that perilesional areas support recovery of speech in the chronic phase post-stroke regardless of the site of the lesion. The study has implications for the understanding of functional recovery as well as for the paradigms used in fMRI to localise speech production areas. Specifically, a variety of speech tasks are required to elicit activation that is representative of the range of cortical involvement in speech in healthy adults and that also allows for accurate reporting of the extent of recovery experienced in patients

Learning From Early Attempts to Generalize Darwinian Principles to Social Evolution

Copyright University of Hertfordshire & author.Evolutionary psychology places the human psyche in the context of evolution, and addresses the Darwinian processes involved, particularly at the level of genetic evolution. A logically separate and potentially complementary argument is to consider the application of Darwinian principles not only to genes but also to social entities and processes. This idea of extending Darwinian principles was suggested by Darwin himself. Attempts to do this appeared as early as the 1870s and proliferated until the early twentieth century. But such ideas remained dormant in the social sciences from the 1920s until after the Second World War. Some lessons can be learned from this earlier period, particularly concerning the problem of specifying the social units of selection or replication

Abnormal negative feedback processing in first episode schizophrenia: evidence from an oculomotor rule switching task

Background. Previous studies have shown that patients with schizophrenia are impaired on executive tasks, where positive and negative feedbacks are used to update task rules or switch attention. However, research to date using saccadic tasks has not revealed clear deficits in task switching in these patients. The present study used an oculomotor ‘ rule switching ’ task to investigate the use of negative feedback when switching between task rules in people with schizophrenia. Method. A total of 50 patients with first episode schizophrenia and 25 healthy controls performed a task in which the association between a centrally presented visual cue and the direction of a saccade could change from trial to trial. Rule changes were heralded by an unexpected negative feedback, indicating that the cue-response mapping had reversed. Results. Schizophrenia patients were found to make increased errors following a rule switch, but these were almost entirely the result of executing saccades away from the location at which the negative feedback had been presented on the preceding trial. This impairment in negative feedback processing was independent of IQ. Conclusions. The results not only confirm the existence of a basic deficit in stimulus–response rule switching in schizophrenia, but also suggest that this arises from aberrant processing of response outcomes, resulting in a failure to appropriately update rules. The findings are discussed in the context of neurological and pharmacological abnormalities in the conditions that may disrupt prediction error signalling in schizophrenia

Development of a Modified Cervical Collar to Eliminate Overheating and Dysphagia Side Effects

Currently, thousands of people each year require the use of a rigid cervical collar. The collars are used in situations of emergency, as well as in situations of precaution, when spinal injury is or may be present. There are many different styles and sizes of cervical collars available on the market today; however, common side effects are noticed when wearing the collars that may reduce the effectiveness to the patient. Often patients complain of general discomfort issues or may suffer from more serious side effects such as pressure sores, increased intracranial pressure, dysphagia, and abnormal distraction within the upper spine. A need exists for the modification of current cervical collars to reduce the painful or uncomfortable side effects associated with wearing them which would, in turn, increase the effectiveness of the therapy that the collar provides to the spine. There are two main components of most cervical collar designs: the rigid outer shell and the inner padding. Both of these components have been considered by our design team in the modification design to improve the efficacy of the cervical collar and to reduce side effects from wearing them. The main goals of this project were to reduce the overall discomfort patients experience that is associated with overheating and dysphagia side effects. As a team, we have researched and tested many materials to determine the best fit for our modified cervical collar. The tests included an end user survey that determined the overall comfortability between the available collars, a cold temperature retention test that showed how long the prospective cooling materials would maintain lower temperatures, and an in-collar temperature test that looked at the temperatures of the materials within the lining of a collar As a team, we have designed a rigid cervical collar that utilizes a slightly flexible, but durable 1/16th inch polyethylene outer shell with padded gel inserts. The outer shell is a two piece design that incorporates the favorable concepts of currently manufactured collars. The two pieces were cut using a scroll saw and molded using an application of heat to the desired positions. There are multiple cut outs in the plastic of both pieces that give flexibility when fitting the collar and the pieces can be connected using velcro straps. The inner “cooling system” is composed of two hydrogels: TheraPearl Technology freezable beads and a pressure activated cooling pad marketed by The Green Pet Shop. The cooling materials will then be wrapped together in polyolefin shrink wrap and placed within specified cutout positions in the antimicrobial padding. Finally the components will be covered in a heat resistant cloth material to ensure direct contact with the skin is compatible and comfortable for the patient. The modifications focus on reducing the hot spots on the cheeks, chin, and neck that are commonly associated with discomfort in patients, will address the discomfort of the chin and neck associated with dysphagia, and will also maintain the rigidity and restriction of motion necessary of the collar. Testing on the efficacy of the design concepts brought forth is still in progress, but we believe the modified cervical collar can increase patient comfort levels and reduce overheating

Isospin splitting of the nucleon mean field

The isospin splitting of the nucleon mean field is derived from the Brueckner theory extended to asymmetric nuclear matter. The Argonne V18 has been adopted as bare interaction in combination with a microscopic three body force. The isospin splitting of the effective mass is determined from the Brueckner-Hartree-Fock self-energy: It is linear acording to the Lane ansatz and such that $m^*_n > m^*_p$ for neutron-rich matter. The symmetry potential is also determined and a comparison is made with the predictions of the Dirac-Brueckner approach and the phenomenological interactions. The theoretical predictions are also compared with the empirical parametrizations of neutron and proton optical-model potentials based on the experimental nucleon-nucleus scattering and the phenomenological ones adopted in transport-model simulations of heavy-ion collisions. The direct contribution of the rearrangement term due to three-body forces to the single particle potential and symmetry potential is discussed.Comment: 8 pages, 10 figure

‘This Adds Another Perspective’: Qualitative Descriptive Study Evaluating Simulation-Based Training for Health Care Assistants, to Enhance the Quality of Care in Nursing Homes

open access articleMuch of the UK’s ageing population lives in care homes, often with complex care needs including dementia. Optimal care requires strong clinical leadership, but opportunities for staff development in these settings are limited. Training using simulation can enable experiential learning in situ. In two nursing homes, Health Care Assistants (HCAs) received training in clinical communication skills (Situation-Background-Assessment-Recommendation Education through Technology and Simulation, SETS: group training with an actor simulating scenarios); and dementia (A Walk Through Dementia, AWTD: digital simulation, delivered one-to-one). In this qualitative descriptive study, we evaluated the potential of this training to enhance HCAs’ clinical leadership skills, through thematic analysis of 24 semi-structured interviews with HCAs (before/after training) and their managers and mentors. Themes were checked by both interviewers. HCAs benefitted from watching colleagues respond to SETS scenarios and reported greater confidence in communicating with registered healthcare professionals. Some found role-play participation challenging. AWTD sensitised HCAs to the experiences of residents with dementia, and those with limited dementia experience gained a fuller understanding of the disease’s effects. Staffing constraints affected participation in group training. Training using simulation is valuable in this setting, particularly when delivered flexibly. Further work is needed to explore its potential on a larger scale